Embodiments of the present invention generally provide improved surgical and/or robotic devices, systems, and methods.
Minimally invasive medical techniques are aimed at reducing the amount of extraneous tissue which is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. Millions of surgeries are performed each year in the United States. Many of these surgeries can potentially be performed in a minimally invasive manner. However, only a relatively small number of surgeries currently use these techniques due to limitations in minimally invasive surgical instruments and techniques and the additional surgical training required to master them.
Minimally invasive telesurgical systems for use in surgery are being developed to increase a surgeon's dexterity as well as to allow a surgeon to operate on a patient from a remote location. Telesurgery is a general term for surgical systems where the surgeon uses some form of remote control, e.g., a servomechanism, or the like, to manipulate surgical instrument movements rather than directly holding and moving the instruments by hand. In such a telesurgery system, the surgeon is provided with an image of the surgical site at the remote location. While viewing typically a three-dimensional image of the surgical site on a suitable viewer or display, the surgeon performs the surgical procedures on the patient by manipulating master control input devices, which in turn control the motion of robotic instruments. The robotic surgical instruments can be inserted through small, minimally invasive surgical apertures to treat tissues at surgical sites within the patient, such apertures resulting in the trauma typically associated with open surgery. These robotic systems can move the working ends of the surgical instruments with sufficient dexterity to perform quite intricate surgical tasks, often by pivoting shafts of the instruments at the minimally invasive aperture, sliding of the shaft axially through the aperture, rotating of the shaft within the aperture, and/or the like.
The servomechanism used for telesurgery will often accept input from two master controllers (one for each of the surgeon's hands) and may include two or more robotic arms or manipulators. Mapping of the hand movements to the image of the robotic instruments displayed by the image capture device can help provide the surgeon with accurate control over the instruments associated with each hand. In many surgical robotic systems, one or more additional robotic manipulator arms are included for moving an endoscope or other image capture device, additional surgical instruments, or the like.
A variety of structural arrangements can be used to support the surgical instrument at the surgical site during robotic surgery. The driven linkage or “slave” is often called a robotic surgical manipulator, and exemplary linkage arrangements for use as a robotic surgical manipulator during minimally invasive robotic surgery are described in U.S. Provisional Application No. 61/654,764 filed Jun. 1, 2012, entitled “Commanded Reconfiguration of a Surgical Manipulator Using the Null Space”, and U.S. Pat. Nos. 6,758,843; 6,246,200; and 5,800,423, the full disclosures of which are incorporated herein by reference in their entirety. These linkages often make use of a parallelogram arrangement to hold an instrument having a shaft. Such a manipulator structure can constrain movement of the instrument so that the instrument shaft pivots about a remote center of spherical rotation positioned in space along the length of the rigid shaft. By aligning this center of rotation with the incision, point to the internal surgical site (for example, with a trocar or cannula at an abdominal wall during laparoscopic surgery), an end effector of the surgical instrument can be positioned safely by moving the proximal end of the shaft using the manipulator linkage without imposing dangerous forces against the abdominal wall. Alternative manipulator structures are described, for example, in U.S. Pat. Nos. 7,594,912, 6,702,805; 6,676,669; 5,855,583; 5,808,665; 5,445,166; and 5,184,601, the full disclosures of which are incorporated herein by reference in their entirety.
While the new robotic surgical systems and devices have proven highly effective and advantageous, still further improvements would be desirable. In some cases, the master controller(s) used by the surgeon have a number of degrees of freedom more than or equal to the number of degrees of freedom which the end effectors of the remotely controlled robotic manipulator arms and/or tools have. In such cases, controllers that are used to control the robotic manipulator arms and/or tools may become overconstrained. For example, where the remote tool is a rigid endoscope extending through a minimally invasive aperture, two orientational degrees of freedom may not be available within the workspace (those associated with a tool wrist near an end effector, e.g., wrist pitch and yaw). Accordingly, the robotic manipulator with endoscope only has four degrees of freedom at its tip. In practice, these mathematical problems can become tangible, resulting in a sluggish, unresponsive feel to the surgeon which is undesirable. Further problems can arise when tools having different degrees of freedom are used with the same robotic surgical manipulator. For example, a surgeon may wish to use jaws having three degrees of freedom, and then replace the jaws with a suction device having two degree of freedom. Even further problems can arise when using estimated joint positions to control tool movements in situations where input and output degrees of freedom differ. Such situations may result in numerical errors being imposed into the joint position estimations resulting in undesired tool movements.
For these and other reasons, it would be advantageous to provide improved devices, systems, and methods for surgery, robotic surgery, and other robotic applications. It would be particularly beneficial if these improved technologies provided the ability to effectively control robotic manipulator arms and/or tools with end effectors having a number of degrees of freedom fewer than the number of degrees of freedom of a master controller manipulated by a surgeon. It would be even more beneficial if these improved technologies allowed the same computation engine to be used for all instruments of the robotic system, thereby reducing controller complexity and costs while increasing flexibility.